This invention relates to acoustical imaging and, more specifically, relates to a transmitter for generating ultrasound waves.
Digital ultrasound scanners typically must handle a wide variety of transmit frequencies and waveforms for different clinical applications. It is advantageous to have multiple waveforms simultaneously loaded to facilitate quick changes between different applications. Assuming a fixed clock applies words of transmit data to the transmit circuitry, the characteristic definition of each of these waveforms inefficiently consumes memory. Low frequency waveforms need more words of data than high frequency waveforms. Complicated waveforms require more bits per word than simple square waves. Moreover, as clinical techniques advance, the mixture of desired waveforms changes, making it impossible to accurately predict the needed memory structures. A flexible transmit memory is needed to efficiently handle all of these waveforms.